<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by pinniped:
Doubtful? I don't get it...if you do it on separate airlines, you haven't violated anyone's terms of service, so there is nothing to "catch". (I think we're all talking about nested tickets or maybe back-to-back tickets. I have never heard the term "ticket stacking".)</font>
The risk being, although you might be able to procure an online connection for your bags if the two distinct airlines have interlinked systems, that your first flight is delayed and you bust your connection.
If its all booked on the same stock, then the airline is obliged to protect you on a later flight. If it is booked on different stock, you might be stuck in the middle of nowhere with little option other than to buy a full-Y to get home.